<div class="progress-bar" #progressBar>
  <div class="bar-inner">
    <!-- 背景 -->
    <div class="progress" #progress></div>
    <!-- 小圆点 -->
    <div class="progress-btn-wrapper" #progressBtn (mousedown)="progressTouchStart($event)"
      (mouseup)="progressMouseUp($event)" (mouseleave)= "progressMouseleave()" (mousemove)="progressTouchMove($event)">
      <div class="progress-btn"></div>
    </div>
  </div>
</div>
